Unique design allows you to install the weight before or after gluing the in insert into the arrow shaft. Tapped back allows you to stack weights which makes them ideal for experimenting with your foc. Able to use on all carbon express .244/.234 Standard arrow inserts, .244 50 Grain brass inserts, and .203 Aluminum half-out inserts. Current standard half-out inserts do not have thread back but by 2024 or earlier standard half-out inserts will have threaded back to able to use the screw-in weights.